Este trabalho descreve um estudo da reação de ancoramento de H[Ru(III)Cl2(H2EDTA)].4.5 H2O na superfície da sílica gel funcionalizada (SF) com o composto [3-(2-aminoetil)aminopropil]trimetoxissilano (AEATS), gerando por meio de ligação amida o composto dimérico (EDTA)2Ru2(IV,IV) na superfície da sílica modificada. A oxidação da água por esse complexo imobilizado na superfície da sílica foi observada pela formação de O2 e decréscimo do pH, originando a sílica modificada SF-AEATS/(EDTA)2Ru2(III1/2 ,III1/2). Este dímero ancorado foi caracterizado por espectroscopia eletrônica e vibracional e também por espectroscopia de EPR. O comportamento eletroquímico de um eletrodo de pasta de carbono modificado com a sílica SF-AEATS/(EDTA)2Ru2(III1/2 ,III1/2) também foi estudado.

The present paper deals with the reaction of oxidative dimerization of the H[Ru(III)Cl2(H2EDTA)].4.5 H2O complex on the surface of silica gel functionalized (SF) with [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEATS), generating the dimeric (EDTA)2Ru2(IV,IV) complex immobilized on the surface of this silica through the coordination with amide bonds. The oxidation of water by the anchored dimeric complex proceeded rapidly and was observed by the evolution of O2 and the decrease in pH, yielding the SF-AEATS/(EDTA)2Ru2(III1/2 ,III1/2). This anchored dimer was characterized by electronic, vibrational and EPR spectroscopies. The electrochemical behavior of a modified carbon paste electrode prepared with SF-AEATS/(EDTA)2Ru2(III1/2 ,III1/2) was also studied.

Silica gel was functionalized with [3-(2-aminoethyl)aminopropyl]trimethoxysilane group (SF-AEATS) and the characterization by chemical analysis (N) and infrared spectroscopy confirmed the functionalization. The capacity of the modified silica to adsorb the complex Ru(III)-EDTA from ethanolic solution was studied. The selectivity coefficients of the complex formed on the support obtained was (Gñ), 2,07 x 10(4) L/mol and the average number of ligand bonded by one metal ion on the support (ñ) was ~ 1.